A precise determination of the CKM angle $\textit{γ}$ from $$ {B}_s^0 $$ oscillations in $$ {B}_s^0\to {D}_s^{\mp }{K}^{\pm } $$ decays offers a critical test of the Standard Model and probes for new physics. We present a comprehensive study on the prospects of measuring $\textit{γ}$ at a future Tera-$\textit{Z}$ factory, utilizing the baseline detector concept of the Circular Electron Positron Collider (CEPC). A two-dimensional simultaneous fit framework, incorporating flavor tagging, decay time resolution modeling, and acceptance corrections, is developed using full Monte Carlo simulations of $$ {B}_s^0\to {D}_s^{\mp}\left(\to {K}^{\mp }{K}^{\pm }{\pi}^{\mp}\right){K}^{\pm } $$ decays and inclusive background processes. The effective flavor tagging power reaches 23.6%, while the decay time resolution is determined to be 26 fs. Projecting to full statistics of signal events across three dominant $$ {D}_s^{-} $$ decay channels, we estimate a statistical precision of $\textit{σ}$($\textit{γ}$) = 0$\textit{.}$69 , which corresponds to 4.1 Tera-$\textit{Z}$ boson equivalent data. This study has established the feasibility of sub-degree level $\textit{γ}$ measurements at a $\textit{Z}$ factory, highlighting its unique advantages in time-dependent $\textit{CP}$ violation studies through ultra-precise vertexing and background suppression capabilities.

China

Ji Peng

Mingrui Zhao

Xiaolin Wang

Manqi Ruan

Hengne Li

Shanzhen Chen

Prospect for measurement of $\textit{CP}$-violating observables in $$ {B}_s^0\to {D}_s^{\mp }{K}^{\pm } $$ decays at a future $\textit{Z}$ factory

By analyzing 4.5 fb of $\textit{e}$ $\textit{e}$ collision data accumulated with the BESIII detector at center-of-mass energies ranging from 4599.53 MeV to 4698.82 MeV, we report the measurement of the absolute branching fraction (BF) of the inclusive decay $$ {\Lambda}_c^{+}\to {K}_S^0X $$ using the double-tag technique. The result is $$ \mathcal{B}\left({\Lambda}_c^{+}\to {K}_S^0X\right) $$ = (10.9 $\textit{±}$ 0.2 $\textit{±}$ 0.1)%, where the first uncertainty is statistical and the second is systematic. This result indicates that there are still undiscovered decay channels containing $$ {K}_S^0 $$ in the final state with a combined BF of (3.0 $\textit{±}$ 0.4)%. The BF of the inclusive decay $$ {\Lambda}_c^{+}\to {\overline{K}}^0/{K}^0X $$ is calculated to be $$ \mathcal{B}\left({\Lambda}_c^{+}\to {\overline{K}}^0/{K}^0X\right) $$ = (21.8 $\textit{±}$ 0.4 $\textit{±}$ 0.2)%, The result is in agreement with the prediction of the statistical isospin model.

M. Ablikim

Russia

M. Achasov

Sweden

P. Adlarson

X. Ai

Germany

R. Aliberti

Italy

A. Amoroso

Q. An

Y. Bai

O. Bakina

Y. Ban

H.R. Bao

Poland

V. Batozskaya

Mongolia

K. Begzsuren

N. Berger

M. Berlowski

M. Bertani

D. Bettoni

F. Bianchi

E. Bianco

A. Bortone

I. Boyko

United States

R. Briere

A. Brueggemann

H. Cai

M. Cai

X. Cai

A. Calcaterra

G. Cao

N. Cao

Türkiye

S. Cetin

X. Chai

J. Chang

G. Che

Y. Che

G. Chelkov

C. Chen

Chao Chen

G. Chen

H. Chen

M. Chen

S. Chen

T. Chen

X. Chen

Y. Chen

Z. Chen

South Korea

S. Choi

X. Chu

G. Cibinetto

F. Cossio

J. Cui

H. Dai

J. Dai

A. Dbeyssi

R. Boer

D. Dedovich

C. Deng

Z. Deng

A. Denig

I. Denysenko

M. Destefanis

F. Mori

B. Ding

X. Ding

Y. Ding

J. Dong

L. Dong

M. Dong

X. Dong

M. Du

S. Du

Y. Duan

Z. Duan

P. Egorov

G. Fan

J. Fan

Y. Fan

J. Fang

S. Fang

W. Fang

Y. Fang

R. Farinelli

L. Fava

F. Feldbauer

G. Felici

C. Feng

J. Feng

Y. Feng

M. Fritsch

C. Fu

J. Fu

Improved measurement of absolute branching fraction of the inclusive decay $$ {\Lambda}_c^{+}\to {K}_S^0X $$

Initiated by the recent observation of a flattened line shape of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>I</mi><msup><mi>J</mi><mrow><mi>P</mi><mi>C</mi></mrow></msup><mo>=</mo><mn>0</mn><msup><mn>0</mn><mrow><mo>−</mo><mo>+</mo></mrow></msup></math> around 1.4–1.5 GeV in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mi>S</mi></msub><msub><mi>K</mi><mi>S</mi></msub><msup><mi>π</mi><mn>0</mn></msup></math> invariant mass spectrum by BESIII, we make a systematic partial wave analysis 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><msub><mi>η</mi><mi>X</mi></msub><mo stretchy="false">→</mo><mi>γ</mi><mi>K</mi><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mi>π</mi></math> based on an isobaric approach. We demonstrate that in the scenario of the first radial excitations of the isoscalar pseudoscalar from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>K</mi><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mi>π</mi></math> threshold to about 1.6 GeV the non-trivial <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>K</mi><mi>S</mi></msub><msub><mi>K</mi><mi>S</mi></msub><msup><mi>π</mi><mn>0</mn></msup></math> invariant mass spectrum can be explained by the coupled-channel effects with the presence of the triangle singularity mechanism. It shows that a combined fit of the Dalitz plots, three-body and two-body spectra can be achieved, which suggests that the one-state solution around 1.4–1.5 GeV proposed before still holds well. In particular, we show that the coupled-channel effects between the three important quasi-two-body decay channels, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msup><mrow><mi>K</mi></mrow><mrow><mo>*</mo></mrow></msup><mover accent="true"><mrow><mi>K</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo>+</mo><mi mathvariant="normal">c</mi><mo>.</mo><mi mathvariant="normal">c</mi><mo>.</mo></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>κ</mi><mover accent="true"><mrow><mi>K</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo>+</mo><mi mathvariant="normal">c</mi><mo>.</mo><mi mathvariant="normal">c</mi><mo>.</mo></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo><mi>π</mi></math>, can be well described by taking into account the one-loop corrections in the isobaric approach. This is because the isoscalar pseudoscalar states are coupled to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>*</mo></msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mo>+</mo><mi mathvariant="normal">c</mi><mo>.</mo><mi mathvariant="normal">c</mi><mo>.</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>a</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo><mi>π</mi></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>κ</mi><mover accent="true"><mrow><mi>K</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mo>+</mo><mi mathvariant="normal">c</mi><mo>.</mo><mi mathvariant="normal">c</mi><mo>.</mo></mrow></math>) channels via the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math> waves, respectively. As a consequence, the coupled-channel effects can be largely absorbed into the redefinition of the tree-level effective couplings with the transition amplitudes computed to the order of one-loop corrections. Then, the coupled-channel effects can be estimated by the contributions from the one-loop rescattering amplitudes in comparison with the tree-level ones, where we find that the rescattering contributions from the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi></math> wave into the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi></math> wave, or vice versa, are apparently suppressed in the kinematic region near threshold.

Yin Cheng

Lin Qiu

Qiang Zhao

Understanding the nontrivial isoscalar pseudoscalar structures in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msub><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow></msub><msub><mrow><mi>K</mi></mrow><mrow><mi>S</mi></mrow></msub><msup><mrow><mi>π</mi></mrow><mrow><mn>0</mn></mrow></msup></mrow></math> spectra in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> radiative decay

We investigate the semileptonic decays of charmed mesons to light vector mesons within the framework of light-cone sum rules. Our calculation is performed at leading order in quantum chromodynamics (QCD) coupling, incorporating contributions up to twist-five accuracy from both two-particle and three-particle light-cone distribution amplitudes. Transition form factors are predicted twist by twist to assess the convergence property of the operator product expansion. It is verified that the twist-four and twist-five contributions are indeed negligible for all the decays under consideration. Twist-three dominance is observed for some of the form factors, subject to heavy quark effective field theory interpretation. Branching ratios for the decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mi>ρ</mi><mn>0</mn></msup><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msup><mi>K</mi><mrow><mo>*</mo><mn>0</mn></mrow></msup><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mn>0</mn></msup><mo stretchy="false">→</mo><msup><mi>K</mi><mrow><mo>*</mo><mo>−</mo></mrow></msup><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>+</mo></msup><mo stretchy="false">→</mo><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mrow><mo>*</mo><mn>0</mn></mrow></msup><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> are obtained, and a 10%–20% discrepancy from experimental measurements is found. Our finding indicates that the resonant-width and nonresonant QCD backgrounds effects should be potentially significant, implying the necessity to further implement their contributions in future precision studies of the semileptonic charm decays.

Wang Lin

Xiao-En Huang

Shan Cheng

De-Liang Yao

Semileptonic decays of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>D</mi><mo stretchy="false">→</mo><mi>ρ</mi><msup><mi>l</mi><mo>+</mo></msup><mi>ν</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>D</mi><mrow><mo stretchy="false">(</mo><mi>s</mi><mo stretchy="false">)</mo></mrow></msub><mo stretchy="false">→</mo><msup><mi>K</mi><mo>*</mo></msup><msup><mi>l</mi><mo>+</mo></msup><mi>ν</mi></math> from light-cone sum rules

We study the femtoscopic correlation functions of meson-baryon pairs in the strangeness <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mo>=</mo><mo>−</mo><mn>1</mn></math> sector, employing unitarized s-wave scattering amplitudes derived from the chiral Lagrangian up to next-to-leading order. For the first time, we deliver predictions on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>π</mi><mo>−</mo></msup><mi mathvariant="normal">Λ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>+</mo></msup><msup><mi mathvariant="normal">Ξ</mi><mo>−</mo></msup></math> correlation functions which are feasible to be measured at the Large Hadron Collider. We also demonstrate that the employed model is perfectly capable of reproducing the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>−</mo></msup><mi>p</mi></math> correlation function data measured by the same collaboration, without the need to modify the coupling strength to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mover accent="true"><mi>K</mi><mo stretchy="false">¯</mo></mover><mn>0</mn></msup><mi>n</mi></math> channel, as has been recently suggested. In all cases, the effects of the source size on the correlation are tested. In addition, we present detailed analysis of the different coupled-channel contributions, together with the quantification of the relative relevance of the different terms in the interaction. These calculations require the knowledge of the so-called production weights, for which we present two novel methods to compute them.

Spain

P. Encarnación

A. Feijoo

V. Mantovani Sarti

A. Ramos

Femtoscopic study of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mo>=</mo><mo>−</mo><mn>1</mn></math> meson-baryon interaction: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>−</mo></msup><mi>p</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>π</mi><mo>−</mo></msup><mi mathvariant="normal">Λ</mi></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>+</mo></msup><msup><mi mathvariant="normal">Ξ</mi><mo>−</mo></msup></math> correlations

We investigate Λ production in the ( <math altimg='si146.svg'><msup><mrow><mi>&#960;</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>, <math altimg='si3.svg'><msup><mrow><mi>K</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>) reaction on a 6Li target at <math altimg='si4.svg'><msub><mrow><mi>p</mi></mrow><mrow><msup><mrow><mi>&#960;</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></mrow></msub><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><mn>1.05</mn></math> GeV/ <italic>c</italic>, using the distorted-wave impulse approximation (DWIA) with the Fermi-averaged <math altimg='si5.svg'><msup><mrow><mi>&#960;</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup><mi>n</mi><mo stretchy='false'>&#8594;</mo><msup><mrow><mi>K</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup><mi mathvariant='normal'>&#923;</mi></math> amplitudes. The calculated spectrum is in good agreement with the experimental data, suggesting that <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>4</mn></mrow></mmultiscripts></math>- <italic>d</italic> configurations play a key role in describing the &#923; continuum states of <math altimg='si23.svg'><msubsup><mrow /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>6</mn></mrow></msubsup></math>Li near and above the <math altimg='si8.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><none /><mrow><mn>3</mn></mrow></mmultiscripts><mo linebreak='goodbreak' linebreakstyle='after'>+</mo><mi>d</mi><mo linebreak='goodbreak' linebreakstyle='after'>+</mo><mi mathvariant='normal'>&#923;</mi></math> threshold. Our analysis shows that the <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>4</mn></mrow></mmultiscripts></math> hypernucleus as a hyperfragment is prominently produced through <italic>D</italic>-wave resonances with <math altimg='si9.svg'><msup><mrow><mi>J</mi></mrow><mrow><mi>P</mi></mrow></msup><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><msup><mrow><mn>3</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>, <math altimg='si10.svg'><msup><mrow><mn>2</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>, and <math altimg='si11.svg'><msup><mrow><mn>1</mn></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math> in the <math altimg='si108.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>4</mn></mrow></mmultiscripts><mo linebreak='goodbreak' linebreakstyle='after'>+</mo><mi>d</mi></math> channel at a large momentum transfer <math altimg='si13.svg'><mi>q</mi><mo>&#8771;</mo><mn>360</mn></math>&#8211;400 MeV/ <italic>c</italic>. These findings provide theoretical evidence for the production of a <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>4</mn></mrow></mmultiscripts></math> hyperfragment via a cluster-like mechanism in the 6Li( <math altimg='si146.svg'><msup><mrow><mi>&#960;</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>, <math altimg='si3.svg'><msup><mrow><mi>K</mi></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msup></math>) reaction.

Japan

Toru Harada

Yoshiharu Hirabayashi

Evidence for <math altimg='si1.svg'><mmultiscripts><mrow><mi mathvariant='normal'>He</mi></mrow><mprescripts /><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mn>4</mn></mrow></mmultiscripts></math> hyperfragment production in the 6Li( <italic>&#960;</italic> +, <italic>K</italic> +) reaction

Recently, the Belle II Collaboration reported the branching fraction <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>K</mi><mo>+</mo></msup><mi>ν</mi><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">)</mo><mo>=</mo><mo stretchy="false">(</mo><mn>2.3</mn><mo>±</mo><mn>0.7</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math> with a significance of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3.5</mn><mi>σ</mi></math>, which is <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>2.7</mn><mi>σ</mi></math> above the Standard Model expectation. Motivated by this measurement, we calculate this decay channel at the next-to-leading order and twist-three level using the perturbative QCD approach. By combining lattice QCD data with our results, we obtain form factors with improved reliability. Using these form factors, we estimate the branching ratios 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>K</mi><mo>+</mo></msup></math> semileptonic flavor-changing neutral current decays, including <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> and <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><msup><mo>ℓ</mo><mo>+</mo></msup><msup><mo>ℓ</mo><mo>−</mo></msup></math>. To address the anomalies in these two processes, we introduce a leptoquark model as a new physics scenario. Analyzing five possible types of leptoquarks, we successfully explain the latest experimental measurements and derive further constraints on the leptoquarks. Furthermore, the single leptoquark model becomes invalid once the stringent constraints from process <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>s</mi></msub><mo stretchy="false">→</mo><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>s</mi></msub><mo>−</mo><mover accent="true"><msub><mi>B</mi><mi>s</mi></msub><mo stretchy="true">¯</mo></mover></math> mixing is taken into account.

Chao-Qi Zhang

Jin Sun

Zhi-Peng Xing

Rui-Lin Zhu

Probing <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></math> semileptonic FCNC decay with new physics effects in the PQCD approach

We present a new avenue of the Raychaudhuri Equation (RE) by introducing a non-affine parametrization within the k-essence framework. This modification accounts for non-geodesic flow curves, leading to emergent repulsive effects in cosmic evolution. Using a DBI-type k-essence Lagrangian, we derive a modified RE and demonstrate its ability to address the Hubble tension while predicting a natural emergence of a dynamical dark energy equation of state. Our Bayesian analysis, constrained by cosmological data, supports the theoretical scaling relation of the k-essence field ( <math altimg='si1.svg'><mover accent='true'><mrow><mi>&#981;</mi></mrow><mrow><mo>&#729;</mo></mrow></mover></math>) and the cosmic scale factor ( <italic>a</italic>). Furthermore, we reinterpret the modified RE as an anti-damped harmonic oscillator, we found a caustic avoidance signature, it may reveal classical or quantum-like effects in cosmic expansion. These results suggest a deep connection between scalar field dynamics and modified gravity, offering new perspectives on the nature of the expansion history of the universe.

India

Samit Ganguly

Goutam Manna

Debashis Gangopadhyay

Israel

Bahamas

Eduardo Guendelman

Abhijit Bhattacharyya

Non-affine extensions of the Raychaudhuri equation in the K-essence framework

Two-body decays like $\textit{K}$ → $\textit{πa}$ rank among the most constraining collider probes for new, low-mass, feebly interacting pseudoscalar particles $\textit{a}$. We explore an alternative class of kaon decay modes, specifically three-body decays to $\textit{ππa}$ or $\textit{μμa}$. The former occur at tree level, while the latter is loop-suppressed yet accidentally finite. These modes specifically leverage the accurate tracking capabilities at LHCb. We present an estimation approach for the sensitivity achievable in future searches within these channels. Our argument uses the current $\textit{uncertainty}$ in leading irreducible backgrounds identified for each channel. Our findings suggest that dedicated searches could probe $\textit{f}$ scales between 10 and 10 TeV, highlighting their strong potential. A direct comparison with actual searches, only available in the $\textit{K}$ → $\textit{π}$ $\textit{π}$ $\textit{a}$ channel, supports this conclusion. Finally, we show that, in these searches, reconstruction efficiency maps are such that large efficiencies are naturally aligned with regions of higher yields in Dalitz plots.

France

Maël Cavan-Piton

Diego Guadagnoli

Axel Iohner

Diego Martínez Santos

Ludovico Vittorio

Probing QCD Axions or axion-like particles in three-body $\textit{K}$ decays

We study the $$\Lambda _{b}\rightarrow \Lambda _{c}\bar{D}^{0}K^{-}$$ and $$\Lambda _{b}\rightarrow \Lambda _{c}D^{-}\bar{K}^{0}$$ decays which proceed via a Cabibbo and $$N_c$$ favored process of external emission, and we determine the $$\bar{D}^{0}K^{-}$$ and $$D^{-}\bar{K}^{0}$$ mass distributions close to the $$\bar{D} \bar{K}$$ threshold. For this, we use the tree level contribution plus the rescattering of the meson-meson components, using the extension of the local hidden gauge approach to the charm sector that produces the $$D^*_{s0}(2317)$$ resonance. We observe a large enhancement of the mass distributions close to threshold due to the presence of this resonance below threshold. Next we undertake the inverse problem of extracting the maximum information on the interaction of the $$\bar{D} \bar{K}$$ channels from these distributions, and using the resampling method we find that from these data one can obtain precise values of the scattering lengths and effective ranges, the existence of an $$I=0$$ bound state with a precision of about $$4 \;\mathrm MeV$$ in the mass, plus the $$\bar{D} \bar{K}$$ molecular probability of this state with reasonable precision. Given the fact that the $$\Lambda _{b}\rightarrow \Lambda _{c}\bar{D}^{0}K^{-}$$ decay is already measured by the LHCb collaboration, it is expected that in the next runs with more statistics of the decay, these mass distributions can be measured with precision and the method proposed here can be used to determine the nature of the $$D^*_{s0}(2317)$$ , which is still an issue of debate.

Hai-Peng Li

Wei-Hong Liang

Chu-Wen Xiao

Ju-Jun Xie

Eulogio Oset

Determination of the binding and $\textit{DK}$ probability of the $$D^{*}_{s0}(2317)$$ from the $$(\bar{D}\bar{K})^-$$ mass distributions in $$\Lambda _{b}\rightarrow \Lambda _{c} (\bar{D}\bar{K})^-$$ decays