The <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>2940</mn><mo stretchy="false">)</mo></math>, an open-charm baryon discovered in 2006, has sparked interest due to its “low mass puzzle,” paralleling the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi><mo stretchy="false">(</mo><mn>3872</mn><mo stretchy="false">)</mo></math> in the charmoniumlike sector. Both states challenge conventional hadronic interpretations, with the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi><mo stretchy="false">(</mo><mn>3872</mn><mo stretchy="false">)</mo></math> understood as a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>*</mo></msup><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover></math> molecular state and the <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>2940</mn><mo stretchy="false">)</mo></math> hypothesized as a <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>*</mo></msup><mi>N</mi></math> molecular state. This work investigates the radiative decay modes <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>2940</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><msub><mi mathvariant="normal">Λ</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>2286</mn><mo stretchy="false">)</mo><mi>γ</mi></math>, <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>2940</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><msub><mi mathvariant="normal">Λ</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>2595</mn><mo stretchy="false">)</mo><mi>γ</mi></math>, and <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>2940</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><msub><mi mathvariant="normal">Λ</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>2765</mn><mo stretchy="false">)</mo><mi>γ</mi></math>, analogous to radiative transitions observed in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>X</mi><mo stretchy="false">(</mo><mn>3872</mn><mo stretchy="false">)</mo></math>. Using the one-boson-exchange model to obtain the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>*</mo></msup><mi>N</mi></math> molecular spatial wave function as input, we calculate decay widths and their ratios, finding differences with different quantum number assumptions. Our findings underscore the potential of electromagnetic probes in revealing its nature and highlight the need for dedicated experimental studies to validate these theoretical predictions.

China

Ping Chen

Zi-Le Zhang

Yu Zhuge

Electromagnetic probes revealing the inner structure of the <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>2940</mn><mo stretchy="false">)</mo></math>

The proposed Circular Electron Positron Collider (CEPC) is expected to provide adequate events around the $\textit{Z}$ boson mass pole, allowing high precision determination on the effective weak mixing angle. Specifically, one can acquire large data samples of the $$Z\rightarrow b\bar{b}$$ , $$Z\rightarrow c\bar{c}$$ and $$Z\rightarrow s\bar{s}$$ events with high purity, even though the efficiencies of the jet tagging are limited to ensure a good separation between different flavors. According to recent studies of the detector and reconstruction algorithms, with the new jet tagging method at the CEPC detector which gives a purity of $$99.9\%$$ for the $$b\bar{b}$$ and $$c\bar{c}$$ samples and $$97\%$$ for the $$s\bar{s}$$ sample, the corresponding uncertainties on the effective weak mixing angle determined from those samples are better than $$10^{-4}$$ using data collected within 1 month. It allows high precision determinations of the effective weak mixing angle from different quark flavors especially for $\textit{c}$ and $\textit{s}$ quarks, which is essential to the standard model global test and potential new physics searches.

Zhenyu Zhao

Siqi Yang

Manqi Ruan

Yongfeng Zhu

Minghui Liu

Liang Han

Measurement of the effective weak mixing angle using $$b\bar{b}$$ , $$c\bar{c}$$ and $$s\bar{s}$$ final states at the CEPC

Recent high-precision <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>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math> data from BESIII and Belle are highly useful to understand vector charmonium (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi></math>) pole structures and puzzling line shapes due to the exotic hadron candidates <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi></math>. We, thus, perform a global coupled-channel analysis of most of the available data (ten two-body, nine three-body, and one four-body final states) in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><mrow><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo></mrow><mn>3.75</mn><mtext> </mtext><mo>−</mo><mn>4.7</mn></mrow><mtext> </mtext><mi>GeV</mi></mrow></math>. Not only cross sections, but also invariant-mass distributions of subsystems are fitted. The <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><msup><mi>μ</mi><mo>+</mo></msup><msup><mi>μ</mi><mo>−</mo></msup></math> cross sections are also predicted. Our model includes dozens of (quasi-)two-body states that nonperturbatively couple with each other through bare <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi></math> excitations, particle-exchange, and short-range mechanisms; approximate three-body unitarity is considered. The amplitudes obtained from the fit are analytically continued to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub></math> poles. We find <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi></math> states similar to those in the Particle Data Group listing and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>Y</mi><mo stretchy="false">(</mo><mn>4320</mn><mo stretchy="false">)</mo></math>. Moreover, several <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi></math> states, including new ones, are found close to open-charm thresholds. Trajectories and compositeness of the near-threshold poles suggest dominant hadron-molecule contents in their internal structures. Two <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub></math> poles are found as virtual states <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>∼</mo><mn>40</mn><mtext> </mtext><mtext> </mtext><mi>MeV</mi></math> below the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>D</mi><mo>*</mo></msup><msup><mover accent="true"><mi>D</mi><mo stretchy="false">¯</mo></mover><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msup></math> thresholds, consistent with lattice QCD results. This work presents the first global analysis to determine <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>Z</mi><mi>c</mi></msub></math> poles, thereby paving the way to extracting detailed properties of the prominent exotic hadron candidates from data.

S.X. Nakamura

X.H. Li

H.P. Peng

Z.T. Sun

X.R. Zhou

Global coupled-channel analysis 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>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math> processes in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mrow><msqrt><mrow><mi>s</mi></mrow></msqrt><mo>=</mo></mrow><mn>3.75</mn><mtext> </mtext><mi>to</mi><mtext> </mtext><mn>4.7</mn><mtext> </mtext><mi>GeV</mi></mrow></math>

Fundamental principles of quantum field theory (QFT) such as Lorentz invariance, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi><mi>T</mi></math> symmetry, and locality may be tested to extremely high precision in atomic and molecular spectroscopy. The narrow natural linewidth of rovibrational states in the hydrogen molecular ion <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">H</mi><mn>2</mn><mrow><mo>+</mo></mrow></msubsup></math> and its antimatter counterpart <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mover accent="true"><mi mathvariant="normal">H</mi><mo stretchy="false">¯</mo></mover><mn>2</mn><mrow><mo>−</mo></mrow></msubsup></math> make these ideal candidates, and give <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>O</mi><mo stretchy="false">(</mo><msub><mi>m</mi><mi>p</mi></msub><mo>/</mo><msub><mi>m</mi><mi>e</mi></msub><mo stretchy="false">)</mo></math> increased sensitivity to Lorentz and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi><mi>T</mi></math> violation in the proton sector compared to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">H</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mover accent="true"><mi mathvariant="normal">H</mi><mo stretchy="false">¯</mo></mover></math> atoms. In a previous paper, we presented a detailed analysis of the rovibrational spectrum of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">H</mi><mn>2</mn><mrow><mo>+</mo></mrow></msubsup></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mover accent="true"><mi mathvariant="normal">H</mi><mo stretchy="false">¯</mo></mover><mn>2</mn><mrow><mo>−</mo></mrow></msubsup></math> in an effective QFT encoding Lorentz and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi><mi>T</mi></math> violation, focusing on spin-independent effects. Here, we extend this analysis to include the full hyperfine-Zeeman spectrum and include spin-dependent Lorentz and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi><mi>T</mi></math> violating operators in the effective theory. The results demonstrate how constraints on these symmetry-violating couplings may be extracted from specific rovibrational transitions between hyperfine-Zeeman states in the presence of an applied magnetic field.

United Kingdom

Graham M. Shore

Lorentz and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi><mi>T</mi></math> violation and the hydrogen and antihydrogen molecular ions. II. Hyperfine-Zeeman spectrum

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation in the charmed baryon sector is generally expected to be very small, of order <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup></math> or even smaller. Nevertheless, large long-distance penguin topologies can be induced through final-state rescattering. At the hadron level, they are manifested as the triangle and bubble diagrams. However, these diagrams consist of not only the penguin but also other tree topologies. Therefore, we focus on the flavor structure of the these diagrams and project out their contributions to penguin and tree topologies. The analysis is performed within the framework of the topological diagram approach and the irreducible SU(3) approach in which the SU(3) flavor symmetry of QCD is realized to describe the nonleptonic decays of charmed baryons. <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>C</mi><mi>P</mi></mrow></math> violation at the per mille level is found in the following decay modes: <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi mathvariant="normal">Λ</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo stretchy="false">→</mo><mi>p</mi><msup><mrow><mi>π</mi></mrow><mrow><mn>0</mn></mrow></msup><mo>,</mo><msubsup><mrow><mi mathvariant="normal">Λ</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo stretchy="false">→</mo><mi>p</mi><msup><mrow><mi>η</mi></mrow><mrow><mo>′</mo></mrow></msup><mo>,</mo><msubsup><mrow><mi mathvariant="normal">Ξ</mi></mrow><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow></msubsup><mo stretchy="false">→</mo><msup><mrow><mi mathvariant="normal">Σ</mi></mrow><mrow><mn>0</mn></mrow></msup><mi>η</mi></mrow></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi mathvariant="normal">Ξ</mi></mrow><mrow><mi>c</mi></mrow><mrow><mo>+</mo></mrow></msubsup><mo stretchy="false">→</mo><msup><mrow><mi mathvariant="normal">Σ</mi></mrow><mrow><mo>+</mo></mrow></msup><mi>η</mi></mrow></math>. <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> asymmetries in the last three modes receive sizable contributions from the SU(3)-flavor-singlet hairpin diagram.

Hai-Yang Cheng

Fanrong Xu

Huiling Zhong

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation in hadronic weak decays of charmed baryons in the topological diagrammatic approach

A search is performed for pairs of light pseudoscalar bosons (a) produced from decays of the 125 GeV Higgs boson (h ). The analysis is based on publicly available data collected in 2016 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. The amount of data analyzed corresponds to an integrated luminosity of 16.4 fb . The analysis explores for the first time at the LHC the final state exhibiting two muons and two c-quarks, which originate from flavor-asymmetric decays of the pseudoscalar pair. The search probes the pseudoscalar boson mass interval comprised between 4 and 11 GeV, which represents a region where the light bosons exhibit a considerable Lorentz boost, and thus their decay products overlap. No significant deviation from the standard model expectation is observed. Model-independent upper limits at 95% confidence level are set on the product of the cross section and branching fraction for the $$ {\textrm{h}}_{125}\to \textrm{aa}\to {\mu}^{-}{\mu}^{+}c\overline{c} $$ process relative to the standard model Higgs boson production cross section, reaching a minimum value close to 3$\textit{.}$3 × 10 . The results are interpreted in the context of two Higgs doublets plus singlet models and compared to existing experimental results covering other decay channels. The exclusion limits obtained by this search improve the current constraints set by various LHC searches in scenarios where the coupling of the light boson to up-type quarks is enhanced.

Germany

Danyer Adan

Search for an exotic decay of the 125 GeV Higgs boson to a pair of light pseudoscalars in the final state of two muons and two c-quarks in proton-proton collisions at $$ \sqrt{s}=13 $$ TeV with CMS Open Data

We deploy the Hartree-Fock approximation for all-heavy quark hadrons, including quarkonium, baryons, tetraquarks, pentaquarks, dibaryons and up to the 12-body dibaryon-antidibaryon which completely fill the 1$\textit{s}$ orbital, in a unified manner, with the spinless LO Coulomb interaction and beyond. After treating the $\textit{c}$ and $\textit{b}$ quarks in various combinations, we delve a bit longer on $\textit{t}$-quark bound states. We extend the negative result of Kuchiev, Flambaum and Shuryak on the 12-body topball to now include the NLO QCD potential. We find that none of the examined multitop states should have binding energy exceeding their width in the Standard Model. Additional new-physics interactions can then be constrained by experimental searches for these bound states, assuming they are not detected, at a level somewhat less stringent than standing HEFT bounds, but with different systematics.

Spain

Alejandro Alonso-Valero

Daniel Berzal-Rozalén

Felipe Llanes-Estrada

Mario Pardo

Clara Peset

Hartree-Fock all-heavy $\textit{c}$, $\textit{b}$ multiquarks and constraints on new top-sector physics

We perform a coupled-channels study of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mi>b</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mi>c</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math> tetraquark systems in a molecular approach using a constituent quark model which has been widely used to satisfactorily describe a broad range of properties of heavy quark hadron systems, either conventional or exotic. Within a molecular framework, the interaction in the heavy quark sector is governed by gluon exchange or confinement forces that are inherently color-dependent. While the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>c</mi></msub><msub><mi>B</mi><mi>c</mi></msub></math> system contains two identical quarks, enabling stronger interactions via exchange diagrams, the forces in the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>c</mi></msub><msub><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">)</mo><mo>−</mo><mo stretchy="false">(</mo><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">)</mo></math> systems are expected to be significantly weaker. Consequently, the theoretical and experimental analysis of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup><msubsup><mi>B</mi><mi>c</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup><msubsup><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup></math>, and charmonium-bottomonium bound structures could play a crucial role in clarifying the dominant mechanisms responsible for the formation of fully heavy tetraquarks. For the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mi>b</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math> tetraquark sector, we find several resonance states with different spin-parity quantum numbers. These resonances are characterized by their proximity, but not too close, to the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup><msubsup><mi>B</mi><mi>c</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup></math> thresholds and their large total decay widths, indicating strong decay channels. In contrast, our analysis of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mi>c</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math> tetraquark sector reveals no bound states, virtual states, or resonances; suggesting that tetraquark states of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">)</mo><mo>−</mo><mo stretchy="false">(</mo><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover><mo stretchy="false">)</mo></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup><msubsup><mover accent="true"><mi>B</mi><mo stretchy="false">¯</mo></mover><mi>c</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup></math> molecular type are unlikely to be formed, within our model assumptions.

P.G. Ortega

D.R. Entem

F. Fernández

J. Segovia

Constituent-quark-model based coupled-channels calculation of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>b</mi><mi>b</mi><mover accent="true"><mrow><mi>c</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mover accent="true"><mrow><mi>c</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>b</mi><mi>c</mi><mover accent="true"><mrow><mi>b</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover><mover accent="true"><mrow><mi>c</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow></math> tetraquark systems

Lepton flavor universality is a key prediction of the Standard Model of particle physics, and any violation of it immediately indicates the existence of new physics. Given the recent discrepancy of more than $$4\sigma $$ in charged current semileptonic $\textit{B}$ meson decays and the absence of evident signals at the Large Hadron Collider, independent cross-checks become invaluable. In this context, $$b \rightarrow c$$ semileptonic sum rules based on heavy quark symmetry are interesting, since they allow us to check the consistency of experimental results. In this paper, we report newly found sum rules among angular observables of mesonic and baryonic $$b\rightarrow c l {\overline{\nu }}$$ decays holding exactly in the large mass limit of heavy quarks. Moreover, we investigate corrections to the sum rule in realistic situations and discuss phenomenological implications.

Japan

Motoi Endo

Syuhei Iguro

Tim Kretz

Satoshi Mishima

Ryoutaro Watanabe

$$b \rightarrow c$$ semileptonic sum rule: extension to angular observables

We study the semileptonic decays of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi mathvariant="normal">Ξ</mi></mrow><mrow><mi>b</mi></mrow><mrow><msup><mrow><mo stretchy="false">(</mo></mrow><mrow><mo>′</mo></mrow></msup><mo stretchy="false">)</mo></mrow></msubsup><mo stretchy="false">→</mo><msubsup><mrow><mi mathvariant="normal">Ξ</mi></mrow><mrow><mi>c</mi></mrow><mrow><msup><mrow><mo stretchy="false">(</mo></mrow><mrow><mo>′</mo></mrow></msup><mo stretchy="false">)</mo></mrow></msubsup><mo>ℓ</mo><msub><mrow><mover accent="true"><mrow><mi>ν</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow><mrow><mo>ℓ</mo></mrow></msub></mrow></math> in all lepton channels. To do this, we first obtain the form factors defining these decay modes within the framework of QCD sum rules. Then, using the transition form factors, we compute the decay widths and branching fractions for all lepton channels and compare the results of our calculations with those obtained from other theoretical methods. We also estimate the branching ratios and the ratio of branching fractions at different leptonic channels to provide useful information for future experiments may be planned at different colliders. Such comparison will provide valuable information about the consistency/inconsistency of the Standard Model theory predictions with experimental data in weak semileptonic single heavy baryon decays.

Iran

Z. Neishabouri

Türkiye

K. Azizi

Investigation of the semileptonic decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><msubsup><mrow><mi mathvariant="normal">Ξ</mi></mrow><mrow><mi>b</mi></mrow><mrow><msup><mrow><mo stretchy="false">(</mo></mrow><mrow><mo>′</mo></mrow></msup><mo stretchy="false">)</mo></mrow></msubsup><mo stretchy="false">→</mo><msubsup><mrow><mi mathvariant="normal">Ξ</mi></mrow><mrow><mi>c</mi></mrow><mrow><msup><mrow><mo stretchy="false">(</mo></mrow><mrow><mo>′</mo></mrow></msup><mo stretchy="false">)</mo></mrow></msubsup><mo>ℓ</mo><msub><mrow><mover accent="true"><mrow><mi>ν</mi></mrow><mrow><mo stretchy="false">¯</mo></mrow></mover></mrow><mrow><mo>ℓ</mo></mrow></msub></mrow></math>