The magnitude of the direct CP asymmetry generated during the weak decay of hadrons is attributed to the weak phase and certain strong phases. The weak phase originates from the CKM matrix, while a strong phase may result from the resonance effect produced by the mixing of vector mesons $ V\left\{\rho^{0}(770),\,\omega(782),\,\phi(1020)\right\} $ to $ \pi^+ \pi^- $ meson pairs. $ \rho^{0}(770) $ can decay directly into $ \pi^+ \pi^- $ meson pairs; both $ \omega(782) $ and $ \phi(1020) $ can also decay into $ \pi^+ \pi^- $ meson pairs, with a small contribution from isospin symmetry breaking. The main contribution for the middle state vector meson $ \rho^{0}(770)-\omega(782)-\phi(1020) $ interference is the mix of $ \rho^{0}(770) $ , $ \omega(782)-\rho^{0}(770) $ , and $ \phi(1020)-\rho^{0}(770) $ . We calculated the CP asymmetry and decay branching ratio for $ \bar{B}^0_{s} \rightarrow \pi^+ \pi^- \pi^0 (\bar K ^{0}) $ within the framework of QCD factorization and compared them with previous studies. We also analyzed the $ \bar{B}^0_{s} \rightarrow \pi^+ \pi^- \eta(\eta^{(')}) $ decay process. The results show that the CP asymmetry of these four decay processes is significantly enhanced, especially for the $ \bar{B}^0_{s} \rightarrow \pi^+ \pi^- \bar K ^{0} $ decay process. Moreover, the decay branching ratio also changes under the resonance effect. These results might provide support for the experimental analysis of the $ \bar B^{0}_s $ meson.

China

Xi-Liang Yuan

Chao Wang

Zhuang-Dong Bai

Gang Lü

Role and contribution of the resonance effect for the decay process of ${ \bar {\boldsymbol B}^{\bf 0}_{\boldsymbol s} \boldsymbol\rightarrow \boldsymbol\pi^{+}\boldsymbol\pi^{-}{\boldsymbol P}}$ * Supported by National Natural Science Foundation of China (Project No.11805153) and Natural Science Foundation of Henan Province (Project No.252300420319)

We use a modified relativistic quark model to study the properties of excited charmed and charmed strange mesons. We calculate the masses and wave functions of conventional charmed and charmed strange mesons incorporating both spin and $\textit{S}$-$\textit{D}$ mixing effects and fit parameters of the potential model with known experimental states using differential evolution techniques. Using leading Born-Oppenheimer expansion, we compute the spectrum and wave functions of the first gluonic excited state of charmed and charmed strange mesons. We examine the effects of gluonic excitation on the spectrum of the resulting hybrid mesons. Using our calculated spectrum and wave functions, we determine the radiative transitions of the conventional and hybrid open charm mesons. We compare our calculations with experimental data and other works. We expect our results will be beneficial in the detection of charmed and charmed strange conventional and hybrid mesons.

Pakistan

Saba Noor

Faisal Akram

Bilal Masud

Study of excited $\textit{D}$ and D$_{s}$ mesons in a relativized quark model * F. A. acknowledges HEC grant 20-15728/NRPU/R&D/HEC/2021, Pakistan

Inelastic dark matter models that have two dark matter particles and a massive dark photon can reproduce the observed relic dark matter density without violating cosmological limits. The mass splitting between the two dark matter particles <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mn>1</mn></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mn>2</mn></msub></math>, with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>m</mi><mo stretchy="false">(</mo><msub><mi>χ</mi><mn>2</mn></msub><mo stretchy="false">)</mo><mo>&gt;</mo><mi>m</mi><mo stretchy="false">(</mo><msub><mi>χ</mi><mn>1</mn></msub><mo stretchy="false">)</mo></math>, is induced by a dark Higgs field and a corresponding dark Higgs boson <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>h</mi><mo>′</mo></msup></math>. We present a search for dark matter in events with two vertices, at least one of which must be displaced from the interaction region, and missing energy. Using a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>365</mn><mtext> </mtext><mtext> </mtext><msup><mi>fb</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></math> data sample collected at Belle II, which operates at 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, we observe no evidence for a signal. We set upper limits on the product of the production cross section <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>σ</mi><mrow><mo stretchy="false">(</mo><mrow><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup></mrow><mo stretchy="false">→</mo><msup><mi>h</mi><mo>′</mo></msup><msub><mi>χ</mi><mn>1</mn></msub><msub><mi>χ</mi><mn>2</mn></msub><mo stretchy="false">)</mo></mrow></math>, and the product of branching fractions <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mrow><mo stretchy="false">(</mo><msub><mi>χ</mi><mn>2</mn></msub><mo stretchy="false">→</mo><msub><mi>χ</mi><mn>1</mn></msub><msup><mi>e</mi><mo>+</mo></msup><msup><mi>e</mi><mo>−</mo></msup><mo stretchy="false">)</mo></mrow><mo>×</mo><mi mathvariant="script">B</mi><mrow><mo stretchy="false">(</mo><msup><mi>h</mi><mo>′</mo></msup><mo stretchy="false">→</mo><msup><mi>x</mi><mo>+</mo></msup><msup><mi>x</mi><mo>−</mo></msup><mo stretchy="false">)</mo></mrow></math>, where <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>x</mi><mo>+</mo></msup><msup><mi>x</mi><mo>−</mo></msup></math> indicates <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup><mo>,</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup></math>, or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>K</mi><mo>+</mo></msup><msup><mi>K</mi><mo>−</mo></msup></math>, as functions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>h</mi><mo>′</mo></msup></math> mass and lifetime at the level of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>1</mn></mrow></msup><mtext> </mtext><mtext> </mtext><mi>fb</mi></math>. We set model-dependent upper limits on the dark Higgs mixing angle at the level of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup></math> and on the dark photon kinetic mixing parameter at the level of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></math>. This is the first search for dark Higgs bosons in association with inelastic dark matter.

I. Adachi

L. Aggarwal

H. Ahmed

H. Aihara

N. Akopov

S. Alghamdi

M. Alhakami

A. Aloisio

N. Althubiti

K. Amos

M. Angelsmark

N. Anh Ky

C. Antonioli

D.M. Asner

H. Atmacan

V. Aushev

M. Aversano

R. Ayad

V. Babu

N.K. Baghel

S. Bahinipati

P. Bambade

Sw. Banerjee

S. Bansal

M. Barrett

M. Bartl

J. Baudot

A. Baur

A. Beaubien

F. Becherer

J. Becker

J.V. Bennett

F.U. Bernlochner

V. Bertacchi

M. Bertemes

E. Bertholet

M. Bessner

S. Bettarini

B. Bhuyan

F. Bianchi

T. Bilka

D. Biswas

A. Bobrov

D. Bodrov

A. Bolz

A. Bondar

G. Bonvicini

J. Borah

A. Boschetti

A. Bozek

M. Bračko

P. Branchini

T.E. Browder

A. Budano

S. Bussino

Q. Campagna

M. Campajola

L. Cao

G. Casarosa

C. Cecchi

J. Cerasoli

M.C. Chang

R. Cheaib

P. Cheema

Y.T. Chen

B.G. Cheon

K. Chilikin

J. Chin

K. Chirapatpimol

H.E. Cho

K. Cho

S.J. Cho

S.K. Choi

S. Choudhury

J. Cochran

I. Consigny

L. Corona

J.X. Cui

E. De La Cruz-Burelo

S.A. De La Motte

G. de Marino

G. De Nardo

G. De Pietro

R. de Sangro

M. Destefanis

S. Dey

A. Di Canto

F. Di Capua

J. Dingfelder

Z. Doležal

I. Domínguez Jiménez

T.V. Dong

X. Dong

M. Dorigo

D. Dossett

K. Dugic

G. Dujany

P. Ecker

J. Eppelt

P. Feichtinger

Search for a Dark Higgs Boson Produced in Association with Inelastic Dark Matter at the Belle II Experiment

The observation of collectivity and strangeness enhancement in small collision systems, such as proton-proton (pp) and proton-lead (p-Pb) collisions, challenges traditional assumptions regarding thermalization and particle production mechanisms. In this study, we investigate particle yields and transverse momentum distributions in pp and p-Pb collisions at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>NN</mi></mrow></msub></mrow></msqrt><mo>=</mo><mn>5.02</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></mrow></math> using the EPOS4 event generator, which employs a core-corona framework to model particle production across a variety of system sizes. EPOS4 successfully reproduces many qualitative trends observed in experimental data, including the hardening of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>p</mi><mi mathvariant="normal">T</mi></msub></math> spectra with multiplicity, the hierarchical strangeness enhancement in strange-to-pion ratios, and characteristic modifications of particle yield ratios as a function of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>p</mi><mi mathvariant="normal">T</mi></msub></math> and multiplicity. The microcanonical approach to core hadronization used in EPOS4 seems to provide a more realistic description of small systems compared to grand-canonical treatments. Nonetheless, quantitative discrepancies still persist in describing several physical observables. Future model refinements, including improved core-corona balancing, differential freeze-out conditions for multistrange hadrons, and incorporation of finite strangeness correlation volumes, may be taken into account for enhancing EPOS4’s predictive power and deepening our understanding of the complex dynamics governing the particle production in high-energy collisions.

India

Hirak Kumar Koley

Subikash Choudhury

Argha Deb

Mitali Mondal

Exploring strangeness enhancement and particle production in small collision systems with EPOS4 at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msqrt><mrow><msub><mrow><mi>s</mi></mrow><mrow><mi>NN</mi></mrow></msub></mrow></msqrt></mrow><mtext> </mtext><mo>=</mo><mn>5.02</mn><mtext> </mtext><mtext> </mtext><mi>TeV</mi></mrow></math>

The isospin-singlet scalar meson <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo></math> is hypothesized to consist of two energy eigenstates, forming a mixture of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mfrac><mn>1</mn><msqrt><mn>2</mn></msqrt></mfrac><mo stretchy="false">(</mo><mover accent="true"><mi>u</mi><mo stretchy="false">¯</mo></mover><mi>u</mi><mo>+</mo><mover accent="true"><mi>d</mi><mo stretchy="false">¯</mo></mover><mi>d</mi><mo stretchy="false">)</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi>s</mi><mo stretchy="false">¯</mo></mover><mi>s</mi></math>. Building on this framework, we apply the quantum chromodynamics (QCD) sum rules approach in the background field theory to compute the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo></math> decay constant, yielding <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><msub><mi>f</mi><mn>0</mn></msub></msub><mo stretchy="false">(</mo><msub><mi>μ</mi><mn>0</mn></msub><mo>=</mo><mn>1</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi><mo stretchy="false">)</mo><mo>=</mo><mn>0.386</mn><mo>±</mo><mn>0.009</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math>. Subsequently, we derive the first two <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ξ</mi></math>-moments of the leading-twist light-cone distribution amplitude <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>ϕ</mi><mrow><mn>2</mn><mo>;</mo><msub><mi>f</mi><mn>0</mn></msub></mrow></msub></math>. Using QCD light-cone sum rules, we then calculate the <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><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo></math> transition form factor (TFF) <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mo>+</mo></msub><mo stretchy="false">(</mo><msup><mi>q</mi><mn>2</mn></msup><mo stretchy="false">)</mo></math>, obtaining <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mo>+</mo></msub><mo stretchy="false">(</mo><mn>0</mn><mo stretchy="false">)</mo><mo>=</mo><mn>0.51</mn><msubsup><mn>6</mn><mrow><mo>−</mo><mn>0.024</mn></mrow><mrow><mo>+</mo><mn>0.027</mn></mrow></msubsup></math> at the large-recoil region. We extend <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mo>+</mo></msub><mo stretchy="false">(</mo><msup><mi>q</mi><mn>2</mn></msup><mo stretchy="false">)</mo></math> to the full physical region via a simplified series expansion parametrization, enabling calculations of the differential decay widths and the branching fraction <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msubsup><mi>D</mi><mi>s</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo><mo stretchy="false">(</mo><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><mo stretchy="false">)</mo><msup><mi>e</mi><mo>+</mo></msup><msub><mi>ν</mi><mi>e</mi></msub><mo stretchy="false">)</mo><mo>=</mo><mspace linebreak="goodbreak"></mspace><mo stretchy="false">(</mo><mn>1.78</mn><msubsup><mn>3</mn><mrow><mo>−</mo><mn>0.189</mn></mrow><mrow><mo>+</mo><mn>0.227</mn></mrow></msubsup><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>3</mn></mrow></msup></math>. Our theoretical predictions align well with the latest BESIII Collaboration measurements within reasonable errors.

Dan-Dan Hu

Xing-Gang Wu

Hai-Jiang Tian

Tao Zhong

Hai-Bing Fu

Light-cone sum rules analysis of the semileptonic <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><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo><mspace linebreak="goodbreak"></mspace><mo stretchy="false">(</mo><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><mo stretchy="false">)</mo><msup><mi>e</mi><mo>+</mo></msup><msub><mi>ν</mi><mi>e</mi></msub></math> decay incorporating the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>f</mi><mn>0</mn></msub><mo stretchy="false">(</mo><mn>980</mn><mo stretchy="false">)</mo></math> mixing state twist-2 distribution amplitudes

We investigate radiative corrections to electroweak precision observables, specifically the Peskin-Takeuchi parameters <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>S</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>T</mi></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>U</mi></math>, in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>3</mn><msub><mo stretchy="false">)</mo><mi>C</mi></msub><mo>×</mo><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>3</mn><msub><mo stretchy="false">)</mo><mi>L</mi></msub><mo>×</mo><mi>U</mi><mo stretchy="false">(</mo><mn>1</mn><msub><mo stretchy="false">)</mo><mi>X</mi></msub></math> model (also known as the 331 model) with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>β</mi><mo>=</mo><mo>−</mo><msqrt><mn>3</mn></msqrt></math>. Using the sarah and spheno packages, we compute the mass spectrum and low-energy observables. We show that these parameters place strong constraints on the model, requiring most of the scalar masses to lie in the TeV range or below, and impose indirect bounds on the newly predicted gauge bosons. Furthermore, we demonstrate that the model can accommodate the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math> boson mass anomaly reported by the CDF Collaboration, should future measurements confirm its persistence.

M. Rehman

M.A. Iqbal

Spain

M.E. Gómez

Italy

O. Panella

Radiative corrections to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>S</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>T</mi></mrow></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>U</mi></mrow></math> parameters and their impact on the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>W</mi></math> boson mass in the 331 model

In this work, we investigate the $$\bar{B}_{s}\rightarrow D_{sJ}$$ transitions in the covariant light-front approach, where $$D_{sJ}$$ denotes an $\textit{s}$-wave or $\textit{p}$-wave $$c\bar{s}$$ meson state. We first obtain the transition form factors within the framework of the quark model and then apply the obtained form factors to obtain the branching fractions of semileptonic and nonleptonic decays. We also compare our results with experimental data and other theoretical predictions. We find that some branching fractions are sizable and might be accessible at the Large Hadron Collider (LHC) and future $$e^{+}$$ – $$e^{-}$$ colliders. Our work is expected to be of great value for establishing corresponding decay channels and also be helpful in understanding the nonperturbative quantum chromodynamics (QCD).

 Wuenqi

Run-Hui Li

Zhen-Xing Zhao

Semileptonic and nonleptonic $$\bar{B}_{s}\rightarrow D_{sJ}$$ decays in covariant light-front approach

A search for the production of a single top quark in association with invisible particles is performed using proton-proton collision data collected with the CMS detector at the LHC at $$\sqrt{s}=13$$ TeV, corresponding to an integrated luminosity of 138 fb . In this search, a flavor-changing neutral current produces a single top quark or antiquark and an invisible state nonresonantly. The invisible state consists of a hypothetical spin-1 particle acting as a new mediator and decaying to two spin-1/2 dark matter candidates. The analysis searches for events in which the top quark or antiquark decays hadronically. No significant excess of events compatible with that signature is observed. Exclusion limits at 95% confidence level are placed on the masses of the spin-1 mediator and the dark matter candidates, and are compared to constraints from the dark matter relic density measurements. In a vector (axial-vector) coupling scenario, masses of the spin-1 mediator are excluded up to 1.85 (1.85) TeV with an expectation of 2.0 (2.0) TeV, whereas masses of the dark matter candidates are excluded up to 0.75 (0.55) TeV with an expectation of 0.85 (0.65) TeV.

Armenia

V. Chekhovsky

A. Hayrapetyan

V. Makarenko

A. Tumasyan

Austria

W. Adam

J. Andrejkovic

L. Benato

T. Bergauer

S. Chatterjee

K. Damanakis

M. Dragicevic

P. Hussain

M. Jeitler

N. Krammer

A. Li

D. Liko

I. Mikulec

J. Schieck

R. Schöfbeck

D. Schwarz

M. Sonawane

W. Waltenberger

C.E. Wulz

Belgium

T. Janssen

H. Kwon

T. Laer

P. Mechelen

N. Breugelmans

J. D’Hondt

S. Dansana

A. Moor

M. Delcourt

F. Heyen

Y. Hong

S. Lowette

I. Makarenko

D. Müller

S. Tavernier

M. Tytgat

G. Onsem

S. Putte

D. Vannerom

B. Bilin

B. Clerbaux

A. Das

I. Bruyn

G. Lentdecker

H. Evard

L. Favart

P. Gianneios

A. Khalilzadeh

F. Khan

A. Malara

M. Shahzad

L. Thomas

Search for dark matter production in association with a single top quark in proton-proton collisions at $$\sqrt{{\varvec{s}}}=13$$ TeV