Recent anomalies observed in $ e^+e^- $ nuclear transitions of $ ^8 {{\rm{Be}}} $ , $ ^4 {\rm{He}} $ , and $ ^{12} {\rm{C}} $ by the ATOMKI collaboration may hint at the existence of a vector boson with a mass around 17 MeV, which is referred to as X17. If it exists, this boson would affect similar processes in particle physics, including the Dalitz decays of vector mesons. Recently, the BESIII collaboration measured the Dalitz decay $ D^{*0}\to D^0e^+e^- $ for the first time and reported a $ 3.5\sigma $ excess over the theoretical prediction based on the vector meson dominance (VMD) model. This excess may be another signal of X17. In this study, we investigate the possible effects of X17 on the Dalitz decays $ D^*_{(s)}\to D_{(s)}e^+e^- $ , $ B^*_{(s)}\to B_{(s)}e^+e^- $ , and $ J/\psi\to \eta_ce^+e^- $ . The required hadronic form factors are calculated within the framework of our covariant confined quark model without relying on heavy quark effective theory or the VMD model. We present predictions for the Dalitz decay widths and the ratios $ R_{ee}(V)\equiv \Gamma(V\to Pe^+e^-)/\Gamma(V\to P\gamma) $ within the standard model and in several new physics scenarios involving modifications attributed to X17. Our results are compared with other theoretical calculations.

Vietnam

C.T. Tran

Russia

M.A. Ivanov

A.T.T. Nguyen

Probing the ATOMKI X17 vector boson using Dalitz decays $\textit{V}$ → $\textit{Pe}$ $^{+}$ $\textit{e}$ $^{−}$ * Supported by Ho Chi Minh City University of Technology and Education (T2024-65)

This paper presents the first measurement of $$\psi {(2S)}$$ and $$\chi _{c1}(3872)$$ meson production within fully reconstructed jets. Each quarkonium state (tag) is reconstructed via its decay to the $${{J \hspace{-1.66656pt}/\hspace{-1.111pt}\psi }} $$ ( $$\rightarrow $$ $$\mu ^+\mu ^-$$ ) $$\pi ^+\pi ^-$$ final state in the forward region using proton-proton collision data collected by the LHCb experiment at the center-of-mass-energy of $$13\text {TeV} $$ in 2016, corresponding to an integrated luminosity of $$1.64\,\text {\,fb} ^{-1} $$ . The fragmentation function, presented as the ratio of the quarkonium-tag transverse momentum to the full jet transverse momentum ( $$p_{\textrm{T}} (\text {tag})/p_{\textrm{T}} (\text {jet})$$ ), is measured differentially in $$p_{\textrm{T}} (\text {jet})$$ and $$p_{\textrm{T}} (\text {tag})$$ bins. The distributions are separated into promptly produced quarkonia from proton-proton collisions and quarkonia produced from displaced $\textit{b}$-hadron decays. While the displaced quarkonia fragmentation functions are in general well described by parton-shower predictions, the prompt quarkonium distributions differ significantly from fixed-order non-relativistic QCD (NRQCD) predictions followed by a QCD parton shower.

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

Italy

P. Albicocco

Germany

J. Albrecht

F. Alessio

M. Alexander

Z. Aliouche

P. Alvarez Cartelle

R. Amalric

Brazil

S. Amato

J. Amey

Y. Amhis

China

L. An

L. Anderlini

M. Andersson

A. Andreianov

P. Andreola

M. Andreotti

D. Andreou

A. Anelli

D. Ao

F. Archilli

M. Argenton

Costa Rica

S. Arguedas Cuendis

A. Artamonov

M. Artuso

E. Aslanides

R. Ataíde Da Silva

M. Atzeni

B. Audurier

D. Bacher

I. Bachiller Perea

S. Bachmann

M. Bachmayer

J. Back

P. Baladron Rodriguez

V. Balagura

W. Baldini

L. Balzani

H. Bao

J. Baptista de Souza Leite

C. Barbero Pretel

M. Barbetti

I. Barbosa

R. Barlow

M. Barnyakov

S. Barsuk

W. Barter

M. Bartolini

J. Bartz

J. Basels

Poland

S. Bashir

G. Bassi

B. Batsukh

P. Battista

A. Bay

A. Beck

M. Becker

F. Bedeschi

I. Bediaga

N. Behling

S. Belin

V. Bellee

K. Belous

I. Belov

I. Belyaev

G. Benane

G. Bencivenni

E. Ben-Haim

A. Berezhnoy

R. Bernet

S. Bernet Andres

A. Bertolin

C. Betancourt

F. Betti

J. Bex

Ia. Bezshyiko

J. Bhom

M. Bieker

N. Biesuz

P. Billoir

A. Biolchini

M. Birch

F. Bishop

A. Bitadze

A. Bizzeti

T. Blake

F. Blanc

Measurements of $$\psi (2S)$$ and $$\chi _{c1}(3872)$$ production within fully reconstructed jets

In recent years, the modeling of compact astrophysical objects ($\textit{COs}$) has garnered significant attention from various research groups, particularly in efforts to determine their stable structures. This interest has been further amplified by the incorporation of dark energy as an additional source within the relativistic interior geometries of these stellar objects. In this paper, we present new structural properties of anisotropic, static, and spherically symmetric compact stars, characterized by a two-fluid distribution comprising ordinary baryonic matter and dark energy, within the framework of the gravity theory $\textit{f}$($\textit{R}$). We derive a novel class of exact analytical solutions to the modified field equations by employing the well-established Tolman–Buchdahl solutions as seed ansatz for the $$g_{tt}$$ and $$g_{rr}$$ metric potentials, in conjunction with a linear dark energy equation of state. The unknown parameters involved in these seed solutions, along with the dark energy coupling factor $$\omega $$ , are determined by a smooth matching of the interior and exterior regions in the hypersurface of the boundary. To analyze the physical viability of our model, we apply it to the compact star $\textit{PSR}$ $$J1614-2230$$ , using the widely studied and cosmologically consistent $$f(R)=R+\chi \Big (R^{2}+\eta R^{3}\Big )$$ gravity model. The obtained space-time geometry is assessed on the basis of several physical constraints, including the regularity of metric components, the viability of matter variables, the validity of state parameters and energy conditions, and various stability factors. Additionally, we examine the mass-radius profile, compactness, and surface redshift to ensure the model’s physical acceptability. Notably, our analysis reveals that the maximum allowable mass and compactness of the proposed dark energy star model exceed observational data, providing strong implications within this modified gravity framework. This suggests that such a model has the potential to surpass conventional observational predictions. In conclusion, our results confirm that the proposed solutions are physically viable and realistic, effectively mimicking a stable ultra-compact dark-energy star. These findings offer new insights into the relativistic stellar framework, highlighting the intricate interplay between extended gravity theories and a two-fluid distribution.

Azerbaijan

Hammad Nazar

Pakistan

Ghulam Abbas

M. Shahzad

Asifa Ashraf

Saudi Arabia

Ali Hakami

Ali Mubaraki

Exploring the stability of ultra-compact anisotropic dark energy stars with maximum allowable mass in $$R+\chi (R^{2}+\eta R^{3})$$ gravity

Higgs couplings are essential probes for physics beyond the Standard Model (BSM) since they can be modified by new physics, such as through the Higgs portal interaction   <math> <msup> <mfenced> <mi>H</mi> </mfenced> <mn>2</mn> </msup> <mi>O</mi> </math>  $$ {\left|H\right|}^2\mathcal{O} $$ . These modifications influence Higgs interactions via dimension-6 operators of the form (∂|H|2)2 and |H|6, which are generally expected to be of comparable size. This paper discusses a phenomenon of accidental suppression, where the |H|6 coupling is significantly smaller than (∂|H|2)2. This suppression, arising from the truncation of the tree-level effective potential, lacks a clear symmetry explanation but persists in portal models. This paper aims to inspire further studies on additional instances of accidental suppression without symmetry explanations or a general framework to characterize such suppression. We also discuss constraints, at the HL-LHC and future colliders, on the Wilson coefficients of the two dimension-6 operators for various benchmark scenarios of the concrete model.

Yunjia Bao

Jiayin Gu

Zhen Liu

Chi Shu

Lian-Tao Wang

Accidental suppression of Wilson coefficients in Higgs coupling

This study investigates the nature of the  $$X_0(2900)$$  <math> <mrow> <msub> <mi>X</mi> <mn>0</mn> </msub> <mrow> <mo>(</mo> <mn>2900</mn> <mo>)</mo> </mrow> </mrow> </math>   and  $$\chi _{c0}(3930)$$  <math> <mrow> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>0</mn> </mrow> </msub> <mrow> <mo>(</mo> <mn>3930</mn> <mo>)</mo> </mrow> </mrow> </math>   based on experimental results of the process  $$B^+$$  <math> <msup> <mi>B</mi> <mo>+</mo> </msup> </math>    $$\rightarrow $$  <math> <mo>→</mo> </math>    $$D^+ D^- K^+$$  <math> <mrow> <msup> <mi>D</mi> <mo>+</mo> </msup> <msup> <mi>D</mi> <mo>-</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> </mrow> </math>  . We focus on the S-wave  $$D^{*-}K^{*+}$$  <math> <mrow> <mmultiscripts> <mi>D</mi> <mrow></mrow> <mrow> <mrow></mrow> <mo>∗</mo> <mo>-</mo> </mrow> </mmultiscripts> <mmultiscripts> <mi>K</mi> <mrow></mrow> <mrow> <mrow></mrow> <mo>∗</mo> <mo>+</mo> </mrow> </mmultiscripts> </mrow> </math>   and  $$D_s^+D_s^-$$  <math> <mrow> <msubsup> <mi>D</mi> <mi>s</mi> <mo>+</mo> </msubsup> <msubsup> <mi>D</mi> <mi>s</mi> <mo>-</mo> </msubsup> </mrow> </math>   molecular states, which can be related to the  $$X_0(2900)$$  <math> <mrow> <msub> <mi>X</mi> <mn>0</mn> </msub> <mrow> <mo>(</mo> <mn>2900</mn> <mo>)</mo> </mrow> </mrow> </math>   and  $$\chi _{c0}(3930)$$  <math> <mrow> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>0</mn> </mrow> </msub> <mrow> <mo>(</mo> <mn>3930</mn> <mo>)</mo> </mrow> </mrow> </math>  , respectively. Using effective Lagrangians, we construct the potential kernel of the  $$D^{*-}K^{*+}$$  <math> <mrow> <mmultiscripts> <mi>D</mi> <mrow></mrow> <mrow> <mrow></mrow> <mo>∗</mo> <mo>-</mo> </mrow> </mmultiscripts> <mmultiscripts> <mi>K</mi> <mrow></mrow> <mrow> <mrow></mrow> <mo>∗</mo> <mo>+</mo> </mrow> </mmultiscripts> </mrow> </math>  – $$D^{-}K^{+}$$  <math> <mrow> <msup> <mi>D</mi> <mo>-</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> </mrow> </math>   and  $$D_s^+D_s^-$$  <math> <mrow> <msubsup> <mi>D</mi> <mi>s</mi> <mo>+</mo> </msubsup> <msubsup> <mi>D</mi> <mi>s</mi> <mo>-</mo> </msubsup> </mrow> </math>  – $$D^+D^-$$  <math> <mrow> <msup> <mi>D</mi> <mo>+</mo> </msup> <msup> <mi>D</mi> <mo>-</mo> </msup> </mrow> </math>   interactions with a one-boson-exchange model, and determine the scattering amplitudes and their poles through a quasipotential Bethe–Salpeter equation approach. By incorporating the potential kernel into the three-body decay process  $$B^+$$  <math> <msup> <mi>B</mi> <mo>+</mo> </msup> </math>    $$\rightarrow $$  <math> <mo>→</mo> </math>    $$D^+ D^- K^+$$  <math> <mrow> <msup> <mi>D</mi> <mo>+</mo> </msup> <msup> <mi>D</mi> <mo>-</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> </mrow> </math>  , we evaluate the  $$D^-K^+$$  <math> <mrow> <msup> <mi>D</mi> <mo>-</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> </mrow> </math>   and  $$D^+D^-$$  <math> <mrow> <msup> <mi>D</mi> <mo>+</mo> </msup> <msup> <mi>D</mi> <mo>-</mo> </msup> </mrow> </math>   invariant mass spectra, as well as the Dalitz plot, using Monte Carlo simulation. A satisfactory fit to the  $$D^-K^+$$  <math> <mrow> <msup> <mi>D</mi> <mo>-</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> </mrow> </math>   and  $$D^+D^-$$  <math> <mrow> <msup> <mi>D</mi> <mo>+</mo> </msup> <msup> <mi>D</mi> <mo>-</mo> </msup> </mrow> </math>   invariant mass spectra is achieved after introducing additional Breit–Wigner resonances,  $$X_1(2900)$$  <math> <mrow> <msub> <mi>X</mi> <mn>1</mn> </msub> <mrow> <mo>(</mo> <mn>2900</mn> <mo>)</mo> </mrow> </mrow> </math>  ,  $$\psi (3770)$$  <math> <mrow> <mi>ψ</mi> <mo>(</mo> <mn>3770</mn> <mo>)</mo> </mrow> </math>  , and  $$\chi _{c2}(3930)$$  <math> <mrow> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>2</mn> </mrow> </msub> <mrow> <mo>(</mo> <mn>3930</mn> <mo>)</mo> </mrow> </mrow> </math>  . Prominent signals of the  $$X_0(2900)$$  <math> <mrow> <msub> <mi>X</mi> <mn>0</mn> </msub> <mrow> <mo>(</mo> <mn>2900</mn> <mo>)</mo> </mrow> </mrow> </math>   and  $$\chi _{c0}(3930)$$  <math> <mrow> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>0</mn> </mrow> </msub> <mrow> <mo>(</mo> <mn>3930</mn> <mo>)</mo> </mrow> </mrow> </math>   states appear as peaks in the  $$D^-K^+$$  <math> <mrow> <msup> <mi>D</mi> <mo>-</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> </mrow> </math>   and  $$D^+D^-$$  <math> <mrow> <msup> <mi>D</mi> <mo>+</mo> </msup> <msup> <mi>D</mi> <mo>-</mo> </msup> </mrow> </math>   invariant mass spectra near 2900 and 3930 MeV, respectively. Clear event concentration from the  $$X_0(2900)$$  <math> <mrow> <msub> <mi>X</mi> <mn>0</mn> </msub> <mrow> <mo>(</mo> <mn>2900</mn> <mo>)</mo> </mrow> </mrow> </math>   and  $$\chi _0(3930)$$  <math> <mrow> <msub> <mi>χ</mi> <mn>0</mn> </msub> <mrow> <mo>(</mo> <mn>3930</mn> <mo>)</mo> </mrow> </mrow> </math>   is evident as strips in the Dalitz plot. The results suggest that both  $$X_0(2900)$$  <math> <mrow> <msub> <mi>X</mi> <mn>0</mn> </msub> <mrow> <mo>(</mo> <mn>2900</mn> <mo>)</mo> </mrow> </mrow> </math>   and  $$\chi _{c0}(3930)$$  <math> <mrow> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>0</mn> </mrow> </msub> <mrow> <mo>(</mo> <mn>3930</mn> <mo>)</mo> </mrow> </mrow> </math>   can be interpreted as molecular states, with the inclusion of  $$X_1(2900)$$  <math> <mrow> <msub> <mi>X</mi> <mn>1</mn> </msub> <mrow> <mo>(</mo> <mn>2900</mn> <mo>)</mo> </mrow> </mrow> </math>   and  $$\chi _2(3930)$$  <math> <mrow> <msub> <mi>χ</mi> <mn>2</mn> </msub> <mrow> <mo>(</mo> <mn>3930</mn> <mo>)</mo> </mrow> </mrow> </math>   necessary to describe structures in the  $$D^-K^+$$  <math> <mrow> <msup> <mi>D</mi> <mo>-</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> </mrow> </math>   and  $$D^+D^-$$  <math> <mrow> <msup> <mi>D</mi> <mo>+</mo> </msup> <msup> <mi>D</mi> <mo>-</mo> </msup> </mrow> </math>   invariant mass spectra, respectively.

Zuo-Ming Ding

Qi Huang

Jun He

$$X_0(2900)$$  <math> <mrow> <msub> <mi>X</mi> <mn>0</mn> </msub> <mrow> <mo>(</mo> <mn>2900</mn> <mo>)</mo> </mrow> </mrow> </math>   and  $$\chi _{c0}(3930)$$  <math> <mrow> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>0</mn> </mrow> </msub> <mrow> <mo>(</mo> <mn>3930</mn> <mo>)</mo> </mrow> </mrow> </math>   in process  $$B^+\rightarrow D^+ D^- K^+$$  <math> <mrow> <msup> <mi>B</mi> <mo>+</mo> </msup> <mo>→</mo> <msup> <mi>D</mi> <mo>+</mo> </msup> <msup> <mi>D</mi> <mo>-</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> </mrow> </math>

The quest for supersymmetric (SUSY) particles is among the main search channels currently pursued at the LHC. Particularly, electroweak (EW) particles with masses as low as a few hundred GeV are still viable. Recent searches for the “golden channel”,  $$pp \rightarrow \tilde{\chi }_{2}^0 \tilde{\chi }_{1}^\pm \rightarrow \tilde{\chi }_{1}^0 Z^{(*)} \, \tilde{\chi }_{1}^0 W^{\pm (*)}$$  <math> <mrow> <mi>p</mi> <mi>p</mi> <mo>→</mo> <msubsup> <mover> <mi>χ</mi> <mo>~</mo> </mover> <mrow> <mn>2</mn> </mrow> <mn>0</mn> </msubsup> <msubsup> <mover> <mi>χ</mi> <mo>~</mo> </mover> <mrow> <mn>1</mn> </mrow> <mo>±</mo> </msubsup> <mo>→</mo> <msubsup> <mover> <mi>χ</mi> <mo>~</mo> </mover> <mrow> <mn>1</mn> </mrow> <mn>0</mn> </msubsup> <mmultiscripts> <mi>Z</mi> <mrow></mrow> <mrow> <mo>(</mo> <mrow></mrow> <mo>∗</mo> <mo>)</mo> </mrow> </mmultiscripts> <mspace width="0.166667em"></mspace> <msubsup> <mover> <mi>χ</mi> <mo>~</mo> </mover> <mrow> <mn>1</mn> </mrow> <mn>0</mn> </msubsup> <mmultiscripts> <mi>W</mi> <mrow></mrow> <mrow> <mo>±</mo> <mo>(</mo> <mrow></mrow> <mo>∗</mo> <mo>)</mo> </mrow> </mmultiscripts> </mrow> </math>   show consistent excesses between ATLAS and CMS in the 2 lepton, 3-lepton and mono-jet searches, assuming      and  $$\Delta m:= m_{\tilde{\chi }_{2}^0} - m_{\tilde{\chi }_{1}^0} \approx 20 \,\, \textrm{GeV}$$  <math> <mrow> <mi>Δ</mi> <mi>m</mi> <mo>:</mo> <mo>=</mo> <msub> <mi>m</mi> <msubsup> <mover> <mi>χ</mi> <mo>~</mo> </mover> <mrow> <mn>2</mn> </mrow> <mn>0</mn> </msubsup> </msub> <mo>-</mo> <msub> <mi>m</mi> <msubsup> <mover> <mi>χ</mi> <mo>~</mo> </mover> <mrow> <mn>1</mn> </mrow> <mn>0</mn> </msubsup> </msub> <mo>≈</mo> <mn>20</mn> <mspace width="0.166667em"></mspace> <mspace width="0.166667em"></mspace> <mtext>GeV</mtext> </mrow> </math>  . This mass configuration arises naturally in SUSY scenarios with wino/bino Dark Matter (DM) or higgsino DM. In these scenarios the lightest supersymmetric particle (LSP), assumed to be the lightest neutralino,  $$\tilde{\chi }_{1}^0$$  <math> <msubsup> <mover> <mi>χ</mi> <mo>~</mo> </mover> <mrow> <mn>1</mn> </mrow> <mn>0</mn> </msubsup> </math>  , as a DM candidate is in good agreement with the observed limits on the DM content of the universe, as well as with negative results from Direct Detection (DD) experiments. We analyze these two scenarios with respect to the observed excesses, taking into account all relevant experimental constraints. We show that in particular wino/bino DM with different signs of the SU(2) and U(1) soft SUSY-breaking parameters can describe well the experimental excesses, while being in agreement with all other constraints.

Manimala Chakraborti

Sven Heinemeyer

India

Ipsita Saha

Consistent excesses in the search for  $$\varvec{\tilde{\chi }_{2}^0\tilde{\chi }_{1}^\pm :}$$  <math> <mrow> <msubsup> <mover> <mi>χ</mi> <mo>~</mo> </mover> <mrow> <mn>2</mn> </mrow> <mn>0</mn> </msubsup> <msubsup> <mover> <mi>χ</mi> <mo>~</mo> </mover> <mrow> <mn>1</mn> </mrow> <mo>±</mo> </msubsup> <mo>:</mo> </mrow> </math>   wino/bino vs. Higgsino dark matter

By tagging one or two intact protons in the forward direction, it is possible to select and measure exclusive photon-fusion processes at the LHC. The same processes can also be measured in heavy ion collisions, and are often denoted as ultraperipheral collisions (UPC) processes. Such measurements open up the possibility of probing certain dimension-8 operators and their positivity bounds at the LHC. As a demonstration, we perform a phenomenological study on the γγ → ℓ + ℓ  −  processes, and find out that the measurements of this process at the HL-LHC provide reaches on a set of dimension-8 operator coefficients that are comparable to the ones at future lepton colliders. We also point out that the γq → γq process could potentially have better reaches on similar types of operators due to its larger cross section, but a more detailed experimental study is need to estimate the signal and background rates of this process. The validity of effective field theory (EFT) and the robustness of the positivity interpretation are also discussed.

Probing positivity at the LHC with exclusive photon-fusion processes

A study of   <math> <msubsup> <mi>B</mi> <mi>c</mi> <mo>+</mo> </msubsup> <mo>→</mo> <msub> <mi>χ</mi> <mi>c</mi> </msub> <msup> <mi>π</mi> <mo>+</mo> </msup> </math>  $$ {B}_c^{+}\to {\chi}_c{\pi}^{+} $$  decays is reported using proton-proton collision data, collected with the LHCb detector at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb −1. The decay   <math> <msubsup> <mi>B</mi> <mi>c</mi> <mo>+</mo> </msubsup> <mo>→</mo> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>2</mn> </mrow> </msub> <msup> <mi>π</mi> <mo>+</mo> </msup> </math>  $$ {B}_c^{+}\to {\chi}_{c2}{\pi}^{+} $$  is observed for the first time, with a significance exceeding seven standard deviations. The relative branching fraction with respect to the   <math> <msubsup> <mi>B</mi> <mi>c</mi> <mo>+</mo> </msubsup> <mo>→</mo> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> <msup> <mi>π</mi> <mo>+</mo> </msup> </math>  $$ {B}_c^{+}\to J/\psi {\pi}^{+} $$  decay is measured to be  <math> <mfrac> <msub> <mi>B</mi> <mrow> <msubsup> <mi>B</mi> <mi>c</mi> <mo>+</mo> </msubsup> <mo>→</mo> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>2</mn> </mrow> </msub> <msup> <mi>π</mi> <mo>+</mo> </msup> </mrow> </msub> <msub> <mi>B</mi> <mrow> <msubsup> <mi>B</mi> <mi>c</mi> <mo>+</mo> </msubsup> <mo>→</mo> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> <msup> <mi>π</mi> <mo>+</mo> </msup> </mrow> </msub> </mfrac> <mo>=</mo> <mn>0.37</mn> <mo>±</mo> <mn>0.06</mn> <mo>±</mo> <mn>0.02</mn> <mo>±</mo> <mn>0.01</mn> <mo>,</mo> </math>  $$ \frac{{\mathcal{B}}_{B_c^{+}\to {\chi}_{c2}{\pi}^{+}}}{{\mathcal{B}}_{B_c^{+}\to J/\psi {\pi}^{+}}}=0.37\pm 0.06\pm 0.02\pm 0.01, $$

CERN

A. Alfonso Albero

F. Baryshnikov

A. Battig

A. Beiter

C. Bertella

J. Blank

S. Blusk

V. Bocharnikov

Study of   <math> <msubsup> <mi>B</mi> <mi>c</mi> <mo>+</mo> </msubsup> <mo>→</mo> <msub> <mi>χ</mi> <mi>c</mi> </msub> <msup> <mi>π</mi> <mo>+</mo> </msup> </math>  $$ {B}_c^{+}\to {\chi}_c{\pi}^{+} $$  decays

We explore the first radial excitation  $$X_{\textrm{4c}}^{*}$$  <math> <msubsup> <mi>X</mi> <mrow> <mtext>4c</mtext> </mrow> <mrow> <mrow></mrow> <mo>∗</mo> </mrow> </msubsup> </math>   of the fully charmed diquark-antidiquark state  $$X_{\textrm{4c}}=cc{\overline{c}}{\overline{c}} $$  <math> <mrow> <msub> <mi>X</mi> <mtext>4c</mtext> </msub> <mo>=</mo> <mi>c</mi> <mi>c</mi> <mover> <mi>c</mi> <mo>¯</mo> </mover> <mover> <mi>c</mi> <mo>¯</mo> </mover> </mrow> </math>   built of axial-vector components, and the hadronic molecule  $${\mathcal {M}} =\chi _{c1}\chi _{c1}$$  <math> <mrow> <mi>M</mi> <mo>=</mo> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>1</mn> </mrow> </msub> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>1</mn> </mrow> </msub> </mrow> </math>  . The masses and current couplings of these scalar states are calculated in the context of the QCD two-point sum rule approach. The full widths of  $$X_{\textrm{4c}}^{*}$$  <math> <msubsup> <mi>X</mi> <mrow> <mtext>4c</mtext> </mrow> <mrow> <mrow></mrow> <mo>∗</mo> </mrow> </msubsup> </math>   and  $${\mathcal {M}}$$  <math> <mi>M</mi> </math>   are evaluated by taking into account their kinematically allowed decay channels. We find partial widths of these processes using the strong couplings  $$g_i^{*}$$  <math> <msubsup> <mi>g</mi> <mi>i</mi> <mrow> <mrow></mrow> <mo>∗</mo> </mrow> </msubsup> </math>   and  $$G_i^{(*)}$$  <math> <msubsup> <mi>G</mi> <mi>i</mi> <mrow> <mo>(</mo> <mrow></mrow> <mo>∗</mo> <mo>)</mo> </mrow> </msubsup> </math>   at the  $$X_{\textrm{4c}}^{*}$$  <math> <msubsup> <mi>X</mi> <mrow> <mtext>4c</mtext> </mrow> <mrow> <mrow></mrow> <mo>∗</mo> </mrow> </msubsup> </math>  ( $${\mathcal {M}}$$  <math> <mi>M</mi> </math>   )-conventional mesons vertices computed by means of the QCD three-point sum rule method. The predictions obtained for the parameters  $$m=(7235 \pm 75)~ \textrm{MeV}$$  <math> <mrow> <mi>m</mi> <mo>=</mo> <mo>(</mo> <mn>7235</mn> <mo>±</mo> <mn>75</mn> <mo>)</mo> <mspace width="3.33333pt"></mspace> <mtext>MeV</mtext> </mrow> </math>  ,  $$\Gamma =(144 \pm 18)~\textrm{MeV}$$  <math> <mrow> <mi>Γ</mi> <mo>=</mo> <mo>(</mo> <mn>144</mn> <mo>±</mo> <mn>18</mn> <mo>)</mo> <mspace width="3.33333pt"></mspace> <mtext>MeV</mtext> </mrow> </math>   and  $${\widetilde{m}}=(7180 \pm 120)~\textrm{MeV}$$  <math> <mrow> <mover> <mi>m</mi> <mo>~</mo> </mover> <mo>=</mo> <mrow> <mo>(</mo> <mn>7180</mn> <mo>±</mo> <mn>120</mn> <mo>)</mo> </mrow> <mspace width="3.33333pt"></mspace> <mtext>MeV</mtext> </mrow> </math>  ,  $${\widetilde{\Gamma }}=(169 \pm 21)~\textrm{MeV}$$  <math> <mrow> <mover> <mi>Γ</mi> <mo>~</mo> </mover> <mo>=</mo> <mrow> <mo>(</mo> <mn>169</mn> <mo>±</mo> <mn>21</mn> <mo>)</mo> </mrow> <mspace width="3.33333pt"></mspace> <mtext>MeV</mtext> </mrow> </math>   of these structures, are compared with the experimental data of the CMS and ATLAS Collaborations. In accordance to these results, within existing errors of measurements and uncertainties of the theoretical calculations, both the excited tetraquark and hadronic molecule may be considered as candidates to the resonance X(7300). Detailed analysis, however, demonstrates that the preferable model for X(7300) is an admixture of the molecule  $${\mathcal {M}}$$  <math> <mi>M</mi> </math>   and sizeable part of  $$X_{\textrm{4c}}^{*}$$  <math> <msubsup> <mi>X</mi> <mrow> <mtext>4c</mtext> </mrow> <mrow> <mrow></mrow> <mo>∗</mo> </mrow> </msubsup> </math>  .

S. Agaev

Iran

Türkiye

K. Azizi

B. Barsbay

H. Sundu

Resonance X(7300): excited 2S tetraquark or hadronic molecule  $$\chi _{c1}\chi _{c1}$$  <math> <mrow> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>1</mn> </mrow> </msub> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>1</mn> </mrow> </msub> </mrow> </math>  ?

In this work, a study of the  $$D_s{\bar{D}}_s$$  <math> <mrow> <msub> <mi>D</mi> <mi>s</mi> </msub> <msub> <mover> <mrow> <mi>D</mi> </mrow> <mrow> <mo>¯</mo> </mrow> </mover> <mi>s</mi> </msub> </mrow> </math>   interaction and its couplings to the channels  $$D{\bar{D}}$$  <math> <mrow> <mi>D</mi> <mover> <mrow> <mi>D</mi> </mrow> <mrow> <mo>¯</mo> </mrow> </mover> </mrow> </math>   and  $$J/\psi \phi $$  <math> <mrow> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> <mi>ϕ</mi> </mrow> </math>   is performed in a quasipotential Bethe–Salpeter equation approach. The  $$D_s^+{D}_s^-$$  <math> <mrow> <msubsup> <mi>D</mi> <mi>s</mi> <mo>+</mo> </msubsup> <msubsup> <mi>D</mi> <mi>s</mi> <mo>-</mo> </msubsup> </mrow> </math>   and  $$D^+{D}^-$$  <math> <mrow> <msup> <mi>D</mi> <mo>+</mo> </msup> <msup> <mrow> <mi>D</mi> </mrow> <mo>-</mo> </msup> </mrow> </math>   invariant mass spectra in three-body B decays are investigated in order to understand the origin of X(3960),  $$\chi _{c0}(3930)$$  <math> <mrow> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>0</mn> </mrow> </msub> <mrow> <mo>(</mo> <mn>3930</mn> <mo>)</mo> </mrow> </mrow> </math>  , and  $$X_0(4140)$$  <math> <mrow> <msub> <mi>X</mi> <mn>0</mn> </msub> <mrow> <mo>(</mo> <mn>4140</mn> <mo>)</mo> </mrow> </mrow> </math>   structures reported at LHCb. With the help of effective Lagrangians, the potential kernel can be constructed with meson exchanges, from which the scattering amplitudes can be obtained. By inserting it into the three-body decay processes, the invariant mass spectra can be calculated with an additional Breit–Wigner resonance introduced. The  $$D_s^+{D}_s^-$$  <math> <mrow> <msubsup> <mi>D</mi> <mi>s</mi> <mo>+</mo> </msubsup> <msubsup> <mi>D</mi> <mi>s</mi> <mo>-</mo> </msubsup> </mrow> </math>   invariant mass spectrum in the decay process  $$B^+\rightarrow D^+_sD^-_sK^+$$  <math> <mrow> <msup> <mi>B</mi> <mo>+</mo> </msup> <mo>→</mo> <msubsup> <mi>D</mi> <mi>s</mi> <mo>+</mo> </msubsup> <msubsup> <mi>D</mi> <mi>s</mi> <mo>-</mo> </msubsup> <msup> <mi>K</mi> <mo>+</mo> </msup> </mrow> </math>   is well reproduced, and the X(3960) structure can be explained as a molecular state from the  $$D_s{\bar{D}}_s$$  <math> <mrow> <msub> <mi>D</mi> <mi>s</mi> </msub> <msub> <mover> <mrow> <mi>D</mi> </mrow> <mrow> <mo>¯</mo> </mrow> </mover> <mi>s</mi> </msub> </mrow> </math>   interaction. The state also exhibits as a peak in the  $$D^+{D}^-$$  <math> <mrow> <msup> <mi>D</mi> <mo>+</mo> </msup> <msup> <mrow> <mi>D</mi> </mrow> <mo>-</mo> </msup> </mrow> </math>   invariant mass spectrum in the decay  $$B^+\rightarrow D^+D^-K^+$$  <math> <mrow> <msup> <mi>B</mi> <mo>+</mo> </msup> <mo>→</mo> <msup> <mi>D</mi> <mo>+</mo> </msup> <msup> <mi>D</mi> <mo>-</mo> </msup> <msup> <mi>K</mi> <mo>+</mo> </msup> </mrow> </math>  , however, it is too narrow to reproduce the experimental structure around 3930 MeV. The dip around 4140 MeV in the  $$D_s^+{D}_s^-$$  <math> <mrow> <msubsup> <mi>D</mi> <mi>s</mi> <mo>+</mo> </msubsup> <msubsup> <mi>D</mi> <mi>s</mi> <mo>-</mo> </msubsup> </mrow> </math>   invariant mass spectrum can be reproduced by the additional resonance with interference effect. However, a small bump instead of a dip is produced from the  $$D_s{\bar{D}}_s-J/\psi \phi $$  <math> <mrow> <msub> <mi>D</mi> <mi>s</mi> </msub> <msub> <mover> <mrow> <mi>D</mi> </mrow> <mrow> <mo>¯</mo> </mrow> </mover> <mi>s</mi> </msub> <mo>-</mo> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> <mi>ϕ</mi> </mrow> </math>   coupled-channel effect, which suggests that the  $$X_0(4140)$$  <math> <mrow> <msub> <mi>X</mi> <mn>0</mn> </msub> <mrow> <mo>(</mo> <mn>4140</mn> <mo>)</mo> </mrow> </mrow> </math>   cannot be interpreted as the  $$D_s{\bar{D}}_s-J/\psi \phi $$  <math> <mrow> <msub> <mi>D</mi> <mi>s</mi> </msub> <msub> <mover> <mrow> <mi>D</mi> </mrow> <mrow> <mo>¯</mo> </mrow> </mover> <mi>s</mi> </msub> <mo>-</mo> <mi>J</mi> <mo>/</mo> <mi>ψ</mi> <mi>ϕ</mi> </mrow> </math>   coupling in the current model.

Zuo-ming Ding

Combined analysis on nature of X(3960),  $$\chi _{c0}(3930)$$  <math> <mrow> <msub> <mi>χ</mi> <mrow> <mi>c</mi> <mn>0</mn> </mrow> </msub> <mrow> <mo>(</mo> <mn>3930</mn> <mo>)</mo> </mrow> </mrow> </math>  , and  $$X_0(4140)$$  <math> <mrow> <msub> <mi>X</mi> <mn>0</mn> </msub> <mrow> <mo>(</mo> <mn>4140</mn> <mo>)</mo> </mrow> </mrow> </math>